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Biomedical subjects

H Morisawa

Publications and source records attributed to H Morisawa.

18 recordsLinked to original sources
PubMed2000

Does hyperuricemia affect mortality? A prospective cohort study of Japanese male workers.

A positive association between hyperuricemia and cardiovascular disease has been reported, but no study has evidenced yet the precise role of serum uric acid in the development of cardiovascular disease. In addition, no epidemiological studies have so far documented a decreased risk of cancer among people with hyperuricemia, even though the antioxidant action of uric acid has recently been stressed to inhibit DNA damage. The present prospective cohort study investigates the relationship between hyperuricemia and health hazards in a Japanese working population. The subjects were 49,413 Japanese male railroad workers, aged 25-60 years at enrollment. Serum uric acid and other baseline data were provided by annual health-survey records from 1975 to 1982. The vital status of the subjects was traced until the end of 1985 for those who remained alive. During an average 5.4-year study period, 984 deaths were recorded. Those with serum uric acid over 8.5 mg/dl showed elevated relative risks (RRs) of death in all causes (RR 1.62, p<0.01), coronary heart disease ( RR 1.52), stroke (RR 2.33, p<0.01), hepatic disease (RR 3.58, p<0.01), and renal failure ( RR 8.52, p<0.01), as compared with those with serum uric acid levels of 5.0-6.4mg/dl. The RR of death in all causes still remains statistically significant when adjusted by age and serum total cholesterol (2.00, p<0.01), age and alcohol intake (1.85, p<0.001), age and smoking (1.69, p<0.001), age and gout treatment (1.61, p<0.05), and also age and BMI (1.50, p< 0.05). On the other hand, the RR of all causes decreased but was still above 1.0 when adjusted by age and blood glucose (1.62), age and systolic blood pressure (1.32), age and GOT (1.23), and also age and history of cardiovascular disease (1.17). These results showed that hyperuricemia has a strong association with the RRs of death in all causes, coronary heart disease, stroke, hepatic disease and renal failure, and indicated that serum uric acid seems to be a considerable risk factor for reduced life expectancy.

Adult↗
PubMed1996

Development of an integrated radiotherapy network system.

PURPOSE: To introduce the process of developing an integrated radiotherapy network. METHODS AND MATERIALS: We developed a new radiotherapy treatment-planning system in 1987 that we named the Computer Tomography (CT) simulator. CT images were immediately transported to multiimage monitors and to a planning computer, and treatment planning could be performed with the patient lying on the CT couch. The results of planning were used to guide a laser projector, and radiation fields were projected onto the skin of the patient. Since 1991, an integrated radiotherapy network system has been developed, which consists of a picture archiving and communicating system (PACS), a radiotherapy information database, a CT simulator, and a linear accelerator with a multileaf collimator. RESULTS: Clinical experience has been accumulated in more than 1,000 patients. Based on our 7 years of experience, we have modified several components of our original CT simulator and have developed a second generation CT simulator. A standard protocol has been developed for communication between the CT scanner, treatment planning computer, and radiotherapy apparatus using the Ethernet network. As a result, treatment planning data can be transported to the linear accelerator within 1 min after completion of treatment planning. CONCLUSION: This system enables us to make optimal use of CT information and to devise accurate three-dimensional (3D) treatment-planning programs. Our network also allows for the performance of fully computer-controlled dynamic arc conformal therapy.

Computer Communication Networks↗
PubMed1995

Inhibition of neurotropic mouse retrovirus replication in glial cells by synthetic oligo(2'-O-methyl)ribonucleoside phosphorothioates.

Synthetic oligo(2'-O-methyl)ribonucleoside phosphorothioate, FS-25, which is complementary to the splicing acceptor site of neurotropic mouse retrovirus (FrC6 virus), and non-complementary analogs including 2'-O-methylinosine homo oligomer (MIS-25), both inhibited viral infection in glial cells. In addition, FS-25 and MIS-25 partially suppressed viral production of glial cells persistently infected with FrC6 virus. Both FS-25 and MIS-25 potently inhibited reverse transcriptase activity of the FrC6 virus in a cell-free system. Addition of these compounds before or after second-round infection of the FrC6 virus inhibited the accumulation of unintegrated viral DNA. These results indicate that these compounds fundamentally inhibit retrovirus production in glial cells in the same manner in which they inhibit HIV production, by blocking several viral replication pathways including fresh infection, second-round infection, and reverse transcription of the viral genome. Our novel neurotropic retrovirus is a useful experimental model for the development of drugs against HIV infection.

Animals↗
PubMed1994

Precise positioning of intracranial small tumors to the linear accelerator's isocenter, using a stereotactic radiotherapy computed tomography system (SRT-CT).

RT-CT was developed as a simulator using CT scan for radiotherapy. Following three-dimensional treatment planning using CT images, the treatment center and treatment fields are projected to the patients' surface by laser beam on the C arm. The prototype had an accuracy of 3 mm which was equivalent to conventional X-ray simulators but was not adequate for use in stereotactic radiotherapy. A new RT-CT system was developed to have a precise localization capability for stereotactic radiotherapy. Using this stereotactic RT-CT (SRT-CT) after three-dimensional planning, the treatment center is projected to the stereotactic frame automatically. In this study, the values of the x, y and z coordinates of the target center determined by SRT-CT are compared with those determined by the traditional method using CT localizing plates. The discrepancies were within 1.0 mm in 90% and 1.5 mm in 100% of 30 measurements in 16 patients. The disadvantages of SRT-CT may be that the accuracy of localization depends on the quality of calibration of laser beams. The traditional CT localizing method has superiority over SRT-CT because of its solid coordinates but its accuracy is vulnerable to alignment of CT fiducial marker plates. Therefore, the SRT-CT and traditional CT localizing methods would be complementary to each other for precise localization.

Brain Neoplasms↗
PubMed1989

Inhibition of human immunodeficiency virus (HIV-1) replication by synthetic oligo-RNA derivatives.

Several synthetic 2'-O-methyl-RNA oligomers and their derivatives have been evaluated for inhibitory effect against HIV-induced cytopathic effect and expression of the virus specific antigen in cultured MT-4 cells. In this study, oligo(2'-O-methyl)ribonucleoside phosphorothioates showed a potent inhibitory activity with size dependency (25-mer showed it at 1 microM), but by contrast both 2'-O-methylribo- and deoxy-oligomers with normal phosphate linkages failed to inhibit. However, it should be noted that the patched oligo(2'-O-methyl)ribonucleotide (20-mer), in which five linkages at 5'- and three linkages at 3'-ends of normal phosphates were replaced with thiophosphates, has recovered the substantial inhibitory effect. These results show that the size of oligomer and phosphorothioate linkages, probably resistant to exolytic nucleases, are essential for exhibiting antiviral activity.

Base Sequence↗
PubMed1987

Site-directed cleavage of RNA.

Using complementary chimeric oligonucleotides containing deoxyribonucleotides and 2'-O-methylribonucleotides (1), enzymatically synthesized RNA (90 mer) were cleaved at a single site with Escherichia coli RNaseH, either at a hairpin loop or at a stem region. Especially, site-specific cleavage occurred in even the target region being enclosed within a stable, base-paired stem. The method is proved to be generally applicable to RNA containing secondary structures.

Base Sequence↗